Television process and means of realization



March 6, 1928. 1,661,603

A. DAUVILLIER 4 TELEVISION PROCESS AND MEANS OF REALIZATION Filed Aug. 22. 1924 Pa tented 6 1 92'8.

P TENT] OFFICE. v y

'nrnxaivnnn nnuvirmnn, orrmrsrmcn.

' Q IELEVISION rnocnss AND iuEANs or BnALIzn'rIoN.

Application .filed August 22, iezyseml'no. 738,651,- and in France November 29, 1923.

The present "invention describes, a new television process, which isjcharacterized by the fact that the image to be transmitted is analyzed by means of a rotating or oscillating light-distributor selecting at every instant in itself, a spot ofinvariable size, the

. coordinates of which varying in its plane according to an arbitrary law, relatively to a system of reference connected wlth the image; this distributor simultaneously producing currents of variable positions according to thevariations of position of the 'duc'tion oi the spot relatively to, the surface of the image, whose am litudes' are proportional to the said coordinates; the photoelectric current of elementary brightness controlling at the receiving station, by known means, the

brightness of a luminous spotprojected on a screen and put in the correct position by the varyin currents.

v varying currents without any auxiliary device, which is the object of the invention. J

In the form of construction illustrated the light-distributor ofv the transmitting apparatus is'the revolving opaque disc described in the No. 521,746 dated 20th August 1915, for the purpose of analyzing a Rontgen image in the objective lens 1. Any

, disc introducing into two coordinate cir- J cuits, either: 1 "identical elements of E. M. F. 47 connecte. in series in the ordinate circuit 38 ring segments 48 withoutxresisb.

50 7 ance) and identical elements of pote'ntia-l' difspace and time. This disc 21 has the samev angular displacements ofthe disc driven by any sort of motor inside a double fixed col-' lector 44 and 45, a brush 46v carried-by the ference with a linear variationv"(re volving potentiometer) 1n the abscissa: circuit 39 (ring segments" 49 of high resistance): or 2,1 constant elements of d resistance for or It is this direct pro- French Patent Dauvillier disc and theinates and variable elements for abscissae; storage cells being inserted in the coordinate circuits; theresult being that in a complete revv olution of the'disc, the ordinate E. M. F.s

having taken the same number of constant values differing by the samequantity (step variation) as there are holes in the disc, and the abscissae E. M. F.s havin varied line-v arly the same number of times etween zero andthe same maximum value (or inversely). 1

These E. M. F.s present thus variations any known .process such as the triode resistance amplifier of several steps shown at 3. This pliotoelectrieE. M. F. controls at thereceiving station, thru the wires and 61, the instantaneous brightness of the cathodic stream of a Braun tube 16. This control is efiected by applying the E. M. F.s between the. hot wire cathode 17 and the grid diaphragm 19 with resistance shunt 20 to prevent the accumulation of electrostatic charges. I

The coordinate E. M. F .s or varying currents produced by the brush 46 revolvingwith the disc 21. position the cathodic stream in the Braun tube thru the wires 38, 39 and 40 connected to the condenser plates 51, the

diaphragm tube 47 and the condenser plates 50. The plates of condensers 51 and 50 are arranged at right angles to eacl'l other as well known.

From the above it will be seen that the im- 1 age is reproduced by the cathodic stream of the Braun tube which is varied in intensity by the currents from the photoelectric cell and positioned bythe coordinate E. M. F.s.

The moving brush of the apparatus can be a very fine mercury jet in an hydrocarbide atmosphere (Blondel) or a cathodic. stream revolving'or at rest.

-Inboththe'se forms of realization, the. cathode ray oscillogra'ph can also be ree. placed bytwo ordinary oscillographs placed] at. right angles. and carrying mirrors or. slits, or by tuning .forks ofthe same fre-f quencies' asi'those of the-distributor and maintained in series 'by' the. sameplate current. Th'e'photo-electric current thus controls the intensity of a beam of light by means of an electro-optical phenomenon free from inertia as that of Kerr.

Finally the disc described above can form the rotor of a fork operated chronometr'ic motor (Guillet) in series with identical and synchronous receiving discs, all being Polychrome television is obtained by put- P ting in the plane of a first, real auxiliary image a three colour screen whose elementary monochrome grains are proportional to the size of the spot. A similar screen is put in front of the receiving screen (the fluorescent material will then give white light) and can be displaced in two rectangular directions by an amount equal to once or twice the size of the spot.

Wireless television is obtained by the modulation of trains of undamped waves of different frequencies by the brightness and coordinates currents, these wave trains being filtered at the receiving station by known methods.

What I claim as my invention and desire to secure by Letters Patent is:

1. In a television system, a disc rotating in front of the real image to be transmitted, holes distributed both on a spiral and on concentric and equidistant circumferences drawn on the rotary disc so as to select, at every instant, a beam, of invariable size, completely exploring the plane of the image for a single revolution of the disc, and means allowing the rotary disc to simultaneously produce currents the intensities of which are proportional to the variations of coordinates of the beam relative to the image to be transmitted.

2. In a television system, a disc rotating in front of the real image to be transmitted, holes distributed both on a spiral and on concentric and equidistant circumferences drawn on the rotary disc so as to select, at every instant, a beam, of invariable size, completely exploring the plane of the image for a single revolution of the disc, a photoelectric cell receiving the light stream which passes through the holes of the rotary disc, means for amplifying the current thus produced, a cathodic oscillograph, at the receiving station, receiving the current thus amplified which produces variations of intensity of the cathodic stream roduced, and means allowing the rotary disk to simultaneously produce currents which act on the said cathodic stream and the intensities of which are proportional to the variations of the coordinates of the beam movable in the plane of the image to be transmitted.

3. In a television system, a disc rotating in front of the real image to be transmitted, holes distributed both on a spiral and on concentric and equidistant circumferences drawn on the rotary disc, so as to select, at every instant, a beam, of invariable size, completely exploring the plane of the image for a single revolution of the disc, a photoelectric cell receiving the light stream which passes through the holes of the rotary disc, means for amplifyin the current thus produced, a cathodic oscillograph, at the rcceiving station, receiving the current thus amlified which produces variations of intensity of the cathodic stream produced, means allowing the rotary disc to simultaneously produce a current which varies in arithmetic progression according to the variations of ordinates of the beam movable in the plane of the image to be transmitted and a current which varies in steps according to the variations of abscissae of the said beam.

4. In a television system, adisc rotating in front of the real image to be transmitted, holes distributed both on a spiral and on concentric and equidistant circumferences drawn on the rotary disc so as to select, at every instant, a beam, of invariable size completely exploring the plane of the image for a single revolution of the disc, a photo-electric cell receiving the light stream which passes through the holes of the rotary disc, means for'amplifying the current thus produced, a cathodic oscillograph, at the receiving station, receiving the current thus amplified which produces variations of intensity of the cathodic stream produced, a double brush moving at the same time as the rotary disc, a fixed commutator having contacts corresponding to the holes of the rotary disc, elements of constant electromotivc force connecting the consecutive contacts in order to produce currents of ordinates varying in arithmetic proglrssion. and means for simultaneously producing :1 current which varies in steps according to the variations of abscissze. of the beam moving on the image to be transmitted.

5. In a television system, a disc rotating in front of the real image to be transmitted, holes distributed both on a spiral and on concentric and equidistant circumferences drawn on the rotarydisc so as to select, at every instant, a beam, of invariable size, completely exploring the plane of the image for a single revolution of the disc, a photoelectric cell receiving the light stream which passes through the holes of the rotary disc, means for amplifying the current thus produced, a cathodic oscillograph, at the receiving station, receiving the current thus amplified which produces variations of intensity of the cathodic stream produced, a

llu

double brush moving 'at the same time as the rotary disc, a fixed commutator having contacts corresponding to the holes of the rotary disc, elements of constant electromotive force connecting the consecutive contacts in order to produce currents of ordinates varying in arithmetic progression, a second commutator parallel to the first commutator, insulated contacts corresponding to the holes of the disc and connected in shunt to the terminals of a source of current so as to produce a current which varies in steps according to the variations of abscissee of the beam moving on the image to be transmitted.

In testimony whereof I have signed my name to this specification.

ALEXANDRE DAUVILLIER. 

